Re: [patch 09/16] genirq: Add generic msi irq domain support

["Yun Wu (Abel)" <wuyun.wu@huawei.com>]

On 2014/11/12 21:43, Thomas Gleixner wrote:

> From: Jiang Liu <jiang.liu@linux.intel.com>
> 
> Implement the basic functions for MSI interrupt support with
> hierarchical interrupt domains.
> 
> [ tglx: Extracted and combined from several patches ]
> 
> Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
> Cc: Bjorn Helgaas <bhelgaas@google.com>
> Cc: Grant Likely <grant.likely@linaro.org>
> Cc: Marc Zyngier <marc.zyngier@arm.com>
> Cc: Yingjoe Chen <yingjoe.chen@mediatek.com>
> Cc: Yijing Wang <wangyijing@huawei.com>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> ---
>  include/linux/msi.h |   35 +++++++++++++++
>  kernel/irq/Kconfig  |   10 ++++
>  kernel/irq/Makefile |    1 
>  kernel/irq/msi.c    |  119 ++++++++++++++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 165 insertions(+)
> 
> Index: tip/include/linux/msi.h
> ===================================================================
> --- tip.orig/include/linux/msi.h
> +++ tip/include/linux/msi.h
> @@ -77,4 +77,39 @@ struct msi_chip {
>  	void (*teardown_irq)(struct msi_chip *chip, unsigned int irq);
>  };
>  
> +#ifdef CONFIG_GENERIC_MSI_IRQ_DOMAIN
> +struct irq_domain;
> +struct irq_chip;
> +struct device_node;
> +struct msi_domain_info;
> +
> +struct msi_domain_ops {
> +	void		(*calc_hwirq)(struct msi_domain_info *info, void *arg,
> +				      struct msi_desc *desc);
> +	irq_hw_number_t	(*get_hwirq)(struct msi_domain_info *info, void *arg);
> +	int		(*msi_init)(struct irq_domain *domain,
> +				    struct msi_domain_info *info,
> +				    unsigned int virq, irq_hw_number_t hwirq,
> +				    void *arg);
> +	void		(*msi_free)(struct irq_domain *domain,
> +				    struct msi_domain_info *info,
> +				    unsigned int virq);
> +};
> +
> +struct msi_domain_info {
> +	struct msi_domain_ops	*ops;
> +	struct irq_chip		*chip;
> +	void			*data;
> +};
> +
> +int msi_domain_set_affinity(struct irq_data *data, const struct cpumask *mask,
> +			    bool force);
> +
> +struct irq_domain *msi_create_irq_domain(struct device_node *of_node,
> +					 struct msi_domain_info *info,
> +					 struct irq_domain *parent);
> +struct msi_domain_info *msi_get_domain_info(struct irq_domain *domain);
> +
> +#endif /* CONFIG_GENERIC_MSI_IRQ_DOMAIN */
> +
>  #endif /* LINUX_MSI_H */
> Index: tip/kernel/irq/Kconfig
> ===================================================================
> --- tip.orig/kernel/irq/Kconfig
> +++ tip/kernel/irq/Kconfig
> @@ -60,6 +60,16 @@ config IRQ_DOMAIN_HIERARCHY
>  	bool
>  	select IRQ_DOMAIN
>  
> +# Generic MSI interrupt support
> +config GENERIC_MSI_IRQ
> +	bool
> +
> +# Generic MSI hierarchical interrupt domain support
> +config GENERIC_MSI_IRQ_DOMAIN
> +	bool
> +	select IRQ_DOMAIN_HIERARCHY
> +	select GENERIC_MSI_IRQ
> +
>  config HANDLE_DOMAIN_IRQ
>  	bool
>  
> Index: tip/kernel/irq/Makefile
> ===================================================================
> --- tip.orig/kernel/irq/Makefile
> +++ tip/kernel/irq/Makefile
> @@ -6,3 +6,4 @@ obj-$(CONFIG_IRQ_DOMAIN) += irqdomain.o
>  obj-$(CONFIG_PROC_FS) += proc.o
>  obj-$(CONFIG_GENERIC_PENDING_IRQ) += migration.o
>  obj-$(CONFIG_PM_SLEEP) += pm.o
> +obj-$(CONFIG_GENERIC_MSI_IRQ) += msi.o
> Index: tip/kernel/irq/msi.c
> ===================================================================
> --- /dev/null
> +++ tip/kernel/irq/msi.c
> @@ -0,0 +1,119 @@
> +/*
> + * linux/kernel/irq/msi.c
> + *
> + * Copyright (C) 2014 Intel Corp.
> + * Author: Jiang Liu <jiang.liu@linux.intel.com>
> + *
> + * This file is licensed under GPLv2.
> + *
> + * This file contains common code to support Message Signalled Interrupt for
> + * PCI compatible and non PCI compatible devices.
> + */
> +#include <linux/irq.h>
> +#include <linux/irqdomain.h>
> +#include <linux/msi.h>
> +
> +#ifdef CONFIG_GENERIC_MSI_IRQ_DOMAIN
> +int msi_domain_set_affinity(struct irq_data *irq_data,
> +			    const struct cpumask *mask, bool force)
> +{
> +	struct irq_data *parent = irq_data->parent_data;
> +	struct msi_msg msg;
> +	int ret;
> +
> +	ret = parent->chip->irq_set_affinity(parent, mask, force);
> +	if (ret >= 0 && ret != IRQ_SET_MASK_OK_DONE) {
> +		BUG_ON(irq_chip_compose_msi_msg(irq_data, &msg));
> +		irq_chip_write_msi_msg(irq_data, &msg);
> +	}
> +
> +	return ret;
> +}
> +
> +static void msi_domain_activate(struct irq_domain *domain,
> +				struct irq_data *irq_data)
> +{
> +	struct msi_msg msg;
> +
> +	BUG_ON(irq_chip_compose_msi_msg(irq_data, &msg));
> +	irq_chip_write_msi_msg(irq_data, &msg);
> +}
> +
> +static void msi_domain_deactivate(struct irq_domain *domain,
> +				  struct irq_data *irq_data)
> +{
> +	struct msi_msg msg;
> +
> +	memset(&msg, 0, sizeof(msg));
> +	irq_chip_write_msi_msg(irq_data, &msg);
> +}
> +
> +static int msi_domain_alloc(struct irq_domain *domain, unsigned int virq,
> +			    unsigned int nr_irqs, void *arg)
> +{
> +	struct msi_domain_info *info = domain->host_data;
> +	struct msi_domain_ops *ops = info->ops;
> +	irq_hw_number_t hwirq = ops->get_hwirq(info, arg);
> +	int i, ret;
> +
> +	if (irq_find_mapping(domain, hwirq) > 0)
> +		return -EEXIST;

I think we need to check range here.
I fixed this by applying a patch showed in the bottom.

> +
> +	ret = irq_domain_alloc_irqs_parent(domain, virq, nr_irqs, arg);
> +	if (ret < 0)
> +		return ret;
> +
> +	for (i = 0; i < nr_irqs; i++) {
> +		ret = ops->msi_init(domain, info, virq + i, hwirq + i, arg);
> +		if (ret < 0) {
> +			if (ops->msi_free) {
> +				for (i--; i > 0; i--)

while (i--) ?

Regards,
	Abel

> +					ops->msi_free(domain, info, virq + i);
> +			}
> +			irq_domain_free_irqs_top(domain, virq, nr_irqs);
> +			return ret;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static void msi_domain_free(struct irq_domain *domain, unsigned int virq,
> +			    unsigned int nr_irqs)
> +{
> +	struct msi_domain_info *info = domain->host_data;
> +	int i;
> +
> +	if (info->ops->msi_free) {
> +		for (i = 0; i < nr_irqs; i++)
> +			info->ops->msi_free(domain, info, virq + i);
> +	}
> +	irq_domain_free_irqs_top(domain, virq, nr_irqs);
> +}
> +
> +static struct irq_domain_ops msi_domain_ops = {
> +	.alloc		= msi_domain_alloc,
> +	.free		= msi_domain_free,
> +	.activate	= msi_domain_activate,
> +	.deactivate	= msi_domain_deactivate,
> +};
> +
> +struct irq_domain *msi_create_irq_domain(struct device_node *of_node,
> +					 struct msi_domain_info *info,
> +					 struct irq_domain *parent)
> +{
> +	struct irq_domain *domain;
> +
> +	domain = irq_domain_add_tree(of_node, &msi_domain_ops, info);
> +	if (domain)
> +		domain->parent = parent;
> +
> +	return domain;
> +}
> +
> +struct msi_domain_info *msi_get_domain_info(struct irq_domain *domain)
> +{
> +	return (struct msi_domain_info *)domain->host_data;
> +}
> +
> +#endif /* CONFIG_GENERIC_MSI_IRQ_DOMAIN */
> 
> 

diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index cc18182..6d1be00 100644
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -568,6 +568,34 @@ unsigned int irq_find_mapping(struct irq_domain *domain,
 }
 EXPORT_SYMBOL_GPL(irq_find_mapping);

+/**
+ * irq_find_mapping_many() - Find a range of linux irqs from a range of hwirqs.
+ * @domain:	domain owning these hardware interrupts
+ * @hwirq:	start hardware irq number in @domain space
+ * @count:	number of interrupts to find
+ *
+ * Returns the first linux irq number on success, or 0 when not found, or error.
+ */
+int irq_find_mapping_many(struct irq_domain *domain, irq_hw_number_t hwirq,
+			  int count)
+{
+	unsigned int from;
+	int i;
+
+	for (i = from = 0; i < count; i++) {
+		if (!from) {
+			from = irq_find_mapping(domain, hwirq + i);
+			if (from && i)
+				return -1;
+		} else if ((from + i) != irq_find_mapping(domain, hwirq + i)) {
+			return -1;
+		}
+	}
+
+	return from;
+}
+EXPORT_SYMBOL_GPL(irq_find_mapping_many);
+
 #ifdef CONFIG_IRQ_DOMAIN_DEBUG
 static int virq_debug_show(struct seq_file *m, void *private)
 {